1. Field of the Invention
The present invention relates to a motor stop control device utilized in a reel-type gaming machine and a gaming machine using the motor stop control device, the motor stop control device having a motor as a drive source of a reel on which a plurality of symbols are formed and stopping the motor corresponding to a stop instruction from an external.
2. Description of Related Art
Conventionally, in a symbol variable rotation device for a reel-type gaming machine (for example, a Japanese Pachi-slot machine), a reel directly connected to a rotor of a stepping motor (abbreviated as “direct drive manner”) as shown in Japanese Unexamined Publication No. 10-71240. In the symbol variable rotation device utilizing the direct drive manner, all phases of the stepping motor are excited and a detent torque occurs in the stepping motor, thereby smooth stop of the reel is realized. Here, the larger the detent torque becomes the more smooth the reel rapidly stops.
However, in order that a designer designs the reel so as to smoothly stop, the designer has to adopt a precious stepping motor which generates not only a large drive torque but also a large detent torque. In other words, if it is adopted a cheap stepping motor which can generate only a drive torque necessary for drive start thereof, a size of the stepping motor itself is small, thus the detent torque becomes small. Accordingly, stop by all phase excitation cannot be done.
And since there is large imbalance in the detent torque due to each stepping motor, the balance between the detent torque and an inertia of the reel is broken and the stop position of the reel cannot be constantly retained. Therefore, an assembler has to select and use the stepping motor which has a detent torque within a predetermined range and cost of the stepping motor is increased due to that a yield goes down. Further, even if it is adopted the stepping motor having the detent torque within the predetermined range by the above selection, the detent torque of the stepping motor fluctuates more or less within the above predetermined range, therefore the stop position of the stepping motor does not become constant. Thus, in order to make the stop position of the stepping motor more precise, in other words, in order that imbalance of the detent torque does not affect the stop position, the assembler has to prepare the inertia of the reel by attaching a weight to the reel which is attached to the stepping motor and to prepare balance between the detent torque and the inertia in the combination of the stepping motor and the reel. Accordingly, there is a problem that cost of the stepping motor is further increased.